I'm somewhat new to chowhound and did a rudimentary search for Delfino on the board and didn't find it, but forgive me if I'm repeating a topic that's already been well-hashed.
I've been eating at Delfino, which is right in Roslindale Square (754 South St.), for about a year, and I think it's terrific, especially considering the reasonable price for food of its quality (more on that later). I usually order one of the pastas. My favorites are the pappardelle with shrimp (lots of them) and arugula in a pink sauce and its close cousin, penne in pink sauce with porcinis (with shrimp optional). The pasta seems to be homemade and the sauce has this great smoky flavor (not burnt-tasting but nicely smoky). I think the first is about $14 and the second $16 (if you get it with the shrimp). I've also ordered the veal parmigiana, which I like a lot. The portion is gargantuan--definitely enough for at least two meals. Usually I think that mentioning huge portions is the kiss of death, but let me emphasize the quality is terrific; the restaurant isn't trying to make up for mediocre food by giving you a lot of it (a weird logic but one that a lot of restaurants seem to operate on). The veal parm is unbelievably only about $15. We went last night, and my boyfriend ordered the pappadelle bolognese; he reported it excellent (and about $15 as well). You can also get meat dishes (chicken stuffed with red peppers and fontina; steak; veal shank in marsala wine sauce). I've had the lamb chops, which are very tender, and come with a side of veggies and some great garlic mashed potatoes; around $19.
The vegetable antipasto, which I've also ordered many times, comes with grilled eggplant, some salami, roasted red peppers, provolone, and a white bean puree--all either very carefully prepared or well-chosen; sometimes, as it did last night, it also came with fresh ricotta ($9.95). The desserts are limited, but what they have they do well: a really chocolatey, not-too-sweet bread pudding and a really light tiramisu (both around $6). They also have crème brulee and cannolis, which I've never ordered. And, finally, they have a decent chianti for $16/bottle and a bunch of other reasonable wines (since my eye never strays too far from the cheap ones, I can't say much about their other selection, how many or what they're like).
It's not that this is the cheapest restaurant in the world (usually averages for us about $25-$30/person but that's with at least one appetizer and dessert between us and with some wine), but it has a really, really high satisfaction and quality/price ratio. They're also very nice (were quite accommodating when we brought a friend who ordered off the menu--a plate of pasta with olive oil and garlic--and only charged him $6 for it).
They're open from 5-10 p.m. except for Mondays and Tuesdays. I don't think they take reservations and they get really crowded, especially on weekends, so get there early if you don't want to wait a while (but there's a nice bookshop across the street to visit if you do have to wait).